My Father In Law has constant problems with his Onan with less than 200 hours on it. About 90% of the time It will run for for a period of time between 5 and 20 minutes, and then simply shuts down. He has done the following:
Changed oil with Onan brand oil, new spark plug, new fuel filter and new fuel line from fuel filter to carb, new air cleaner, and checked exhaust and spark arrestor for clogs.
It doesn't sound as though it's a fuel related issue, as when it quits, it shuts down immediately with no sputtering, just as if you had turned the switch off.
The unit will restart immediately without problem, and sometimes run forever, or sometimes repeat the short run problem.
The Onan rep in Phoenix could not figure out the problem. Oil level has been check repeatedly, no foaming of the oil is present. Whenever the generator is unplugged from the RV and running without load, the problem does not occur.
Anyone with some magic suggestions that we might check out in between card games?